### RADIOACTIVITY IN MARCELLUS SHALE

CHALLENGE FOR REGULATORS AND WATER TREATMENT PLANTS

Marvin Resnikoff a

a Radioactive Waste Management Associates, Bellows Fa lls, VT 05101, USA

ABSTRACT

Studies by the U.S. Geological Survey and gamma log s of drillers show radium concentrations up to 32 times background concentrations in the Mar cellus shale formation. Brought to the surface in rock cuttings, drilling fluids, flowback water and brine, radium can enter the

environment in several forms. A fraction will be r einserted into deep disposal wells, or go to water treatment plants. Because of its high salini ty, a portion will be spread on highways in the winter. The rock cuttings will go to solid waste l andfills. Over the production cycle, a portion of Marcellus radium plates out on pipes. And an inert radioactive gas, radon, will enter homes when natural gas is used for heating and cooking.

This paper examines the fate and transport of radio nuclides brought to the surface, and the environmental impact in the environment. Regulator s have the task of developing regulations that protect the health and safety of the populatio n. The water treatment industry must develop processes for separating radium from large volumes of waste waters so that surface streams meet regulatory limits. This paper explores these diffe rent waste streams and potential resolutions of these differing problems.

INTRODUCTION

Geologists consider the Marcellus shale formation t o be relatively highly radioactive and regionally extensive. Radioactivity in the Marcellu s shale results from the high content of naturally occurring radioactive uranium and thorium , including their decay products, and potassium elements in the rock. In New York State t he formation ranges from 25 to over 100 feet in thickness and the depth of the base varies from an outcrop to 1000-foot depth by Syracuse to 4000-foot depth by the border with Pennsylvania (Hi ll, 2994).

The areal extent of Marcellus shale is shown in Fig ure 1. As seen, the formation underlies the States of New York, Pennsylvania, eastern Ohio, Wes t Virginia, Virginia, all the way into

Alabama.Figure 1. Areal Extent of Marcellus Shale (NYSERDA, 2009)

The depth to the top of the Marcellus formation in New York State is shown in Figure 2. As seen, the formation is deeper as one goes south.Figure 2. Depth of Marcellus Shale in New York Sta te (NYSERDA, 2009)

In addition to the depth of the Marcellus formation , the thickness varies as well. In New York

State the Marcellus shale thickness increases from less than 25 feet in the western section of the State, Chautauqua County, to 300 feet in the southe astern section of the State, as seen in Figure 3. The dots represent exploratory gas wells.Figure 3. Marcellus shale thickness in New York (NYSERDA, 2009)

RADIOACTIVITY IN MARCELLUS SHALE

Most disinterested scientists agree that the Marcel lus shale contains uranium-238, thorium-232 and their decay products at concentrations signific antly above background. The issue is: how much radioactivity above background? In general, t he radioactivity throughout the vertical depth of rock cuttings appears to be equal to or less tha n 10 picocuries per gram, including K-40. However, at certain depths in each well, the activi ty is significantly higher. The gas industry

knows it has reached the Marcellus shale horizon wh en cores show high gamma ray and high total organic carbon content (TOC). Consider the l og from Beaver Meadows (Figure 4). This well is located near Norwich in Chenango County in upstate New York.Figure 4. Beaver Meadows Core (AAPG, 2010)

As one goes from the shale layer (Union Springs) to the limestone layer (Onondaga Limestone), one sees a major drop in gamma ray and total organi c content. Without going into a discussion of GAPI units, 16.5 GAPI represents 1 pCi/g radium, and 400 GAPI is 24.2 pCi/g radium. As you can see, the GAPI is much greater than 400 unit s, and this also corresponds to very high TOC. These radium concentrations are far higher th an background radium concentrations in New York State (Myrik, 1981), which are 0.85 pCi/g. Other gamma ray logs wells down to the

Marcellus shale horizon in New York State such as t he Shiavone 2, WGI11 and Bergstrasser

wells show similar results.

The logs mentioned above correspond to a geochemica l study of trace elements and uranium in the Devonian shale of the Appalachian Ba sin (Leventhal, 1981) carried out in 1981 by the United States Geological Survey (USGS). The Devonian layer refers to sediment formed350 million years ago from mud in shallow seas. Si nce the layers do not form in a line parallel

to the ground surface, the depth at which Marcellus is found can vary from surface outcroppings to as deep as 7,000 feet or more below the ground s urface along the Pennsylvania border in the Delaware River valley (NYDEC, 2011), and as deep as 9000 feet in Pennsylvania [2].

The USGS study analyzed seventeen cores from wells in Pennsylvania, New York, Ohio, West Virginia, Kentucky, Tennessee, and Illinois. The researchers collected a variety of geochemical data to be used for resource assessment and identification of possible environmental problems. Rather than direct gamma spectroscopy, u ranium was measured in each core with a more appropriate and precise method, delayed-neutro n analysis. I use data from the USGS since it is a reputable and objective government agency.

Although the cores varied in thickness and in depth , geologists identified the Marcellus

Shale stratum in several cores using data on the organic matter (carbon), sulfur, and uranium content of the samples. Table 1 below summarizes t he results from four cores that tapped into the radioactive Marcellus formation. The depths at which the layer was found as well as the uranium measurements are presented.

Location of the Core Depth of Sample (feet) Uranium Content (ppm) Allegheny Cty, PA 7342 – 7465 8.9 – 67.7 Tomkins Cty, NY 1380 – 1420 25 – 53 Livingston Cty, NY 543 – 576 16.6 – 83.7 Knox Cty, OH 1027 – 1127 32.5 – 41.1

Table 1. Uranium Content and Depth of Marcellus Sh ale in Four Cores

The four cores were taken from different geographic al locations, but the characteristics of the identified Marcellus shale layer, specifically the high uranium and carbon content, are

consistent. To compare the uranium content in parts per million (weight) to radioactive concentration in picocuries per gram, we use the correspondence ( HPS, 2007):

2.97 ppm = 1 pCi/g U-238

Using this relationship, the U-238 ranges up to 28 pCi/g, or 32 times background for radium-226, assuming U-238 and Ra-226 are in secular equilibriu m, as it is in the Marcellus Shale formation. That is, the USGS measurements and the GAPI logs ar e consistent. This is our starting point for

the concentrations of Ra-226 in the natural Marcell us Shale formation. The radium itself is found in the pore water of the Marcellus Shale form ation, since radium, under the temperature, pressure and chemical conditions, is preferentially dissolved in the pore water.

FATE AND TRANSPORT OF RADIOACTIVE MATERIALSIf higher levels of radioactivity are present in th e Marcellus shale formation, as shown by gamma

logs, USGS measurements, and statements by DEC, whe re will this radioactivity appear in the aboveground environment and how will DEC regulate t his radioactive waste?

To discuss where uranium, radium and other radioncl ides enter the environment, we consider two components of natural gas development: well dev elopment and production.

Well Development

We are concerned about the horizontal, not the vert ical, component of natural gas wells. As seen in Figure 5, fracking consists of pumping a fluid, proppants and chemicals under high pressure to

Figure 5. Fracking

create fractures along the horizontal region. I’m not going to discuss other chemicals that may contaminate properties, such as arsenic, mercury an d hydrocarbons. The fracture zone may extend up to 200 foot radius from the horizontal bo re. The bore itself may extend horizontally up to a mile. One 4,000-foot lateral wellbore unde rgoing hydraulic fracturing may require between 2.4 million and 7.8 million gallons of wate r. (NYDEC, 2009). During welldevelopment, rock cuttings are produced. These are separated from the drilling fluid by shakers,

shown in Figure 6.

Figure 6. Rock cutting shakers

Rock Cuttings

The drilling fluid itself may be partially recycled and the rock cuttings have been going to solid

waste landfills. Radium is located in the water an d not in the shale rock itself. But solid waste that goes to a solid waste landfill can be, accordi ng to NYS regulations, up to 20% water. An industry lab measured rock cuttings with a gamma de tector; the rock cuttings were shown to be slightly radioactive. On the other hand, NYDEC, in their 2009 Draft Supplemental GEIS, reported radioactivity for two wells in Lebanon and Bath, NY, total radioactivity concentrations of 25.4 +/- 4.6 and 29.2 +/- 4.3 pCi/g, respectivel y, which is consistent with what we expect from the gamma logs and USGS findings. The EPA limits f or radium in surface soil (EPA, 2011) are 5 pCi/g in the top 15 cm, and 15 pCi/g below 15 cm. These rock cuttings, above EPA limits, should be disposed of in a licensed facility for ha ndling radioactive materials, such as Energy Solutions in Clive, Utah. DEC and the Ohio EPA bel ieve they have no jurisdiction over NORM, but if drilling fluid is recycled, the NORM is tech nologically enhanced. I’m not a lawyer, but it appears to me that these agencies do have jurisdict ion over TENORM, if recycled drilling fluids are intermixed with rock cuttings.

Flowback WaterAfter a well is drilled, part of the hydraulic frac turing fluid flows back to the wellhead. This

flowback water constitutes about 10 – 40% of the or iginal pumped volume. (NYTimes, 2011) Since Marcellus shale is of marine origin, it conta ins high levels of salt and NORM which is dissolved in the fluid. (Cornell, 2010) DEC found 13 samples of flowback water from vertical Marcellus shale wells in Schuyler, Chemung and Chen ango counties to contain radioactive concentrations as high as 267 times the limit for d ischarge into the environment and thousands of times the limit for drinking water. (Davies, 2009) Flowback water from horizontal drilling will

be much more radioactive. If flowback water is fed to a water treatment plant, the radium needs to be removed, as we’ll discuss shortly.

Well Production

Once a natural gas well is producing, salt water or brine is brought up with the natural gas, and is separated out at the water gas separator. DEC has sampled brine for radium-226 and radium228. The results are shown in Table 2 below.

Well Town County Ra-226 Ra-228

Maxwell 1C Caton Steuben 7885 234

Frost 2 Orange Schuyler 2647 782

Carpenter 1 Troupsburg Steuben 5352 138

Webster T1 Orange Schuyler 16030 912

Calabro T1 Orange Schuyler 13510 929

Schiavone 2 Reading Schuyler 15140 957

WGI 11 Dix Schuyler 10160 1252

Table 2. Radioactivity in Brine Water (pCi/L)

The radium concentrations in brine are very high. While no one is drinking brine, just to compare these concentrations with drinking water st andards, 5 pCi/L combined radium-226 and 228. That is, the radium concentrations in brine r ange up to 3000 times safe drinking water limits. Under the proposed DEC regulations (NYDEC, 2010), a drill applicant must have a plan to deal with flowback water and brine, and that is where water treatment specialists enter the picture. A practice, which has since been suspende d, is to spread brine, as a de-icing solution, on highways in New York State.

Just to get a handle on the magnitude of the proble m. If hydraulic fracturing were approved, DEC estimates 1600 drilling applications per year; each horizontal well will produce between 2.4million and 7.8 million gallons of flowback water. So we estimate 3.8 to 12.5 billion gallons of

contaminated water per year that has to be treated. This is a small volume compared to the water usage in New York State, but this type of waste pos es additional problems.

In Pennsylvania, much of the 1.3 billion gallons of radioactively-contaminated water produced between 2007 and 2010 was sent to sewage treatment plants. Most sewage plants in the State are not required to monitor for radioactivity, so there are little data. According to sewage plant operators interviewed by the Times (NYTimes, 2011), these plants are not equipped to remove

radioactive material.

As a potential method of treating flowback water an d brine, one can investigate the method of treating uranium mine waste water, which has high c oncentrations of radium. Here radium is precipitated with barium chloride to produce barium sulfate Ba(Ra)SO 4 . Radium is then a particulate that can be filtered. Water treatment plants may then meet SPDES permit limits, and

the filters will have to be sent to a licensed land fill. Other methods include cation exchange softening, lime softening, and sorption onto MnO 2 . A physical process being proposed by Atela, Inc and Casella Waste Systems is distillation, low pressure evaporation. The sludge would then have to be disposed of in a licensed landfill. Vol atiles from this process would have to be captured. It is not clear whether municipal water treatment plants can handle the magnitude of the radioactive waste problem posed by flowback wat er and brine, so that will be a challenge to water treatment professionals, such as you.

Radium scale buildup in gas equipment.

During production, radium dissolved in water, is br ought to the surface. Scale, radium sulfate, plates out on production pipe surfaces. Scale also appears in water/gas separators, feeder lines and condensate tanks. As DEC states, a high concen tration of scale will result in an elevated radiation exposure level at the pipe exterior surfa ce. (NYDEC, 2011) The NYS Department of Health (DOH) proposes a radioactive materials licen se when exposure levels exceed 50 microR/hr (μR/h). (NYDEC, 2012b) Our calculations show that the radium concentrations for an external dose rate of 50 μR/h are far higher tha n the EPA limit of 5 pCi/g. We have found that exposed workers have an increased risk of deve loping cancer. Workers at, and residents near, pipeyards that clean pipe scale will have an additional risk from inhaling radioactive dust. Based on our experience, the proposed DOH regulatio ns are too lax, as we discuss below.

For DEC and DOH to grasp the magnitude of the probl em, we provide one example. At one natural gas well in Texas, 388 pipe joints were pul led after 5 years service. Exposure levels exceeded 50 μR/h in 55% of the 30 foot joints (max, 150 μR/h) 38% were < 50 μR/h and 7% were free of NORM. Similarly, hundreds of pipes at each gas well in New York and Pennsylvania will be contaminated with radium scale . If thousands of gas wells are drilled in New York State, how will DEC and DOH have the resou rces to regulate the industry and track these contaminated pipes? In our experience, oil and gas producing pipes with high external exposure levels have been “donated” to city governm ents for playgrounds in Texas, or to farmers for use in animal corrals in Texas and Kentucky. T hey have been cut up with oxyacetylene torches and welded to fit their use. In the proces s, children and farmers have been directlyexposed to gamma, and inhaled radium. Workers at p ipeyards that cleaned pipes have inhaled

radium-contaminated dust and have developed cancer.

We find that direct gamma exposure levels of 50 μR/ h are much too high. In order to determine

the concentrations of Ra-226 and Ra-228 that corres pond to a dose rate of 50 μ R/hr, we employed the program MicroShield (Grove, 2008), a p rogram used to estimate dose rates due to a specific external radiation source.

As inputs to MicroShield, we assumed an outer pipe diameter of 4 inches (10.16 cm), a scale thickness of 0.2 cm, and a pipe wall thickness of 0 .91 cm, as suggested by the US EPA EPA, 1993b). We could also have used another standard p ipe diameter, 2 7/8 inch. We assumed that each contaminated pipe is 30 feet long, and that ra diation measurements had been taken at the center of the pipe, on contact with the outer pipe wall. From MicroShield, for a pipe with external gamma of 50 μ R/h, we obtain a Ra-226 concentration in scale of 1 ,313.5 pCi/g, and a Ra-228 concentration in scale of 437.8 pCi/g that c orrespond to a dose rate of 50 μ R/h. We

assumed a 3 to 1 ratio of Ra-226 to Ra-228.

As DEC and DOH are well aware, the EPA cleanup stan dard for total radium on soil is 5 pCi/g for the first 15 cm depth and 15 pCi/g 15 cm or mor e below the surface. Pipes, with external radiation 50 μR/h greatly exceed this standard. If these pipes, with NORM <50 μR/h are released for general use, they will be cut up and w elded and the scale will be accessible. Ground contamination could easily exceed 5 pCi/g or 15 pCi /g. Though the 50 μR/h limit has been instituted in several States, in my opinion the DOH -suggested dose rate of 50 μR/h is much too high.

While DEC and DOH intend to regulate joints with ex ternal radiation > 50 μR/h, in practical terms, it is not clear what the State agencies envi sage will become of these radioactive pipes (and separators, feed lines and condensate tanks). Once the oil and gas industry begins production in New York State, this will be a major unresolved pro blem down the road.

Radon in Natural Gas

Yet another significant public health hazard associ ated with drilling for natural gas in the Marcellus Shale formation that should be seriously investigated by the New York State Department of Environmental Conservation (DEC) and other State agencies is the radon hazard. This hazard has the potential for large numbers of lung cancer among natural gas customers. This issue, which has been ignored in the DEC’s Dra ft Supplemental Environmental Impact Statement (NYDEC, 2011), must be addressed in a rev ised Impact Statement and before DEC issues any hydraulic fracturing drilling permits in the Marcellus shale.

Unlike present sources for natural gas, located in Texas and Louisiana, the Marcellus Shale is considerably closer to New York consumers. In addi tion, the radioactive levels at the wellheads in New York are higher than the national average fo r natural gas wells throughout the United

States.In a paper we recently submitted to a journal (RWMA , 2012), RWMA calculated the wellhead

concentrations of radon in natural gas from Marcell us Shale, the time to transit to consumers, particularly New York City residents, and the poten tial health effects of releasing radon, especially in the smaller living quarters found in urban areas.

It is well known that radon (radon-222) is present in natural gas (ATSDR, 1999) (NRC, 1988) and has been known since the early 1900’s (Gesell, 1975). Published reports by R. H. Johnson of the U.S. Environmental Protection Agency (Johnso n, 1973) and C. V. Gogolak of the U.S. Department of Energy (Gogolak, 1980) address this i ssue in depth, as we discuss below. Radon is present in natural gas from Marcellus Shale at m uch higher concentrations than natural gas

from wells in Louisiana and Texas.

Since radon is a decay product of radium-226, to ca lculate radon levels it is necessary to know

the concentrations of radium-226. Based on a USGS study (Leventhal, 1981) and gamma ray logs (also known as GAPI logs) that we have examine d, the radium concentrations in the Marcellus Shale is 8 to 32 times background. This c ompares to an average radium-226 in surface soil in New York State of 0.81 picoCuries per gram (pCi/g).

Using this range of radium concentrations and a sim ple Fortran program that simulates the production of radon in the well bore, and transit t o the wellhead, we calculate a range of radon concentrations at the wellhead between 36.9 picoCur ies per liter (pCi/L) to 2576 pCi/L. The

maximum calculated concentration in Marcellus shale , 2576 pCi/L, is higher than the maximum concentrations found in the Panhandle region of Tex as, 1450 pCi/L. (Johnson, 1973) (Gogolak, 1980).

These wellhead concentrations in Marcellus shale ar e up to 70 times the average in natural gas wells throughout the U.S. The average was calculate d by R. H. Johnson of the U.S. Environmental Protection Agency in 1973 (pre-fracki ng) to be 37 pCi/L (Johnson, 1973) to a maximum of 1450 pCi/L.

In addition, the distance to New York State apartme nts and homes from the Marcellus formation

is 400 miles and sometimes less. This contrasts wi th the distance from the Gulf Coast and other formations, 1800 miles. At 10 mph movement in the pipeline, natural gas containing the radioactive gas, radon, which has a half-life of 3. 8 days, will have three times the radon concentrations than natural gas originating at the Gulf Coast, everything else being equal, which

it is not.

Being an inert gas, radon will not be destroyed whe n natural gas is burned in a kitchen stove.

We have examined published dilution factors and fac tored in numbers for average urban apartments where the dilution factor and the number of air exchanges per hour are less than those of non-urban dwellings. This analysis implies that the radon concentrations in New York City and urban apartments will be greater than the natio nal average.

We assume 11.9 million residents in New York State are affected. This figure is calculated in the following manner: Based on U.S. Department of E nergy figures our calculations assume 4.4million gas stoves in New York State (EIA, 2009). This figure is multiplied by 2.69 persons per

household to determine the number of residents affe cted: this number equals 11.9 million.

We calculate the number of excess lung cancer death s for New York State. Our results: the potential number of fatal lung cancer deaths due to radon in natural gas from the Marcellus shale range from 1,182 to 30,448.

This is an additional number of lung cancer deaths due to radon from Marcellus Shale over deaths from natural radon already impacting New Yor k State homes and their residents. The Draft Supplemental Environmental Impact Stateme nt produced by the New York State Department of Environmental Conservation (NYDEC, 20 11) needs to be revised to take into account this public health and environmental hazard . In the entire 1400 page statement there is only one sentence containing the word “radon” and n o consideration of this significant public

health hazard.

Further, NYDEC needs to independently calculate and measure radon at the wellhead from the Marcellus Shale formation in presently operating we lls before issuing horizontal hydraulic drilling permits in New York State. The presence of processing plants and storage must also be taken into account, and can serve to reduce the rad on concentrations in natural gas delivered to consumers. The present rdsGEIS by DEC discusses no ne of these issues and should be

rewritten.

CONCLUSIONS

Studies by the U.S. Geological Survey and gamma log s of drillers show radium concentrations up to 32 times background concentrations in the Mar cellus shale formation. Brought to the surface in rock cuttings, drilling fluids, flowback water and brine, radium can enter the environment in several forms. During well developm ent, rock cuttings and flowback water containing radium will be bought to the surface. F lowback water from horizontal hydraulic fracturing in the Marcellus formation has high conc entrations of radium that must be disposed in a deep well or properly separated at a water treatm ent facility; the radioactive filters or sludges must go to a licensed landfill. During well produc tion, radioactively-contaminated brine, up to 3000 times safe drinking water limits, must also be treated or disposed in a deep well. Radiumcontaminated scale will form on the down well pipes as well as feeder lines and condensate tanks and these must be safely decontaminated; direct gam ma from these pipes will increase the radiation dose to workers and the general public. Workers at pipeyards have developed cancer from direct gamma radiation and inhaling radioactiv e dust. The scale must be sent to a licensed disposal facility. Radioactive radon gas in natura l gas from the Marcellus shale formation, much closer to the end use market than natural gas from Texas and Louisiana, will enter homes through kitchen stoves. Unless this natural gas is treated or held up, increased radon concentrations in homes and urban apartments will c ause an increase in lung cancer rates.REFERENCES

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